DEMO 200 – Design, Development and Test of a 200 kA DC Busbar Demonstrator

Numerous industrial applications such as aluminum smelters, electrolysis plants and large data centers, require DC feeding currents of several hundred kA. Within the project DEMO200, a demonstrator for a superconducting single-pole 200 kA DC busbar was developed, including suitable current leads. The demonstrator consists of ten identical modules, each with a current capacity of 20 kA. The ten modules are electrically connected in series since a 200 kA DC source was unavailable for testing purposes. Thus, the magnetic self-field effects and Lorentz forces are the same as in the parallel target configuration, but a 20 kA source is sufficient. The demonstrator has a length of 2 m and its ten modules are each based on sixty 12 mm wide REBCO superconducting tapes. The modules are joined in a compact structure with a diameter of 300 mm which withstands thermal contraction and the large Lorentz forces. The demonstrator's design operation temperature was 70 K, but finally the tests were conducted at 77 K. Despite this shortcoming, DEMO200 carried a current of 10 x 18.9 kADC. The current leads and low ohmic connectors complied with the requirements. As a result, SuprAl, a 600 m long busbar, is now being built for TRIMET in Hamburg and is also presented.